A United States-Based Multicenter Retrospective Report of Perioperative Anaphylaxis, 2010-2021.

BACKGROUND: US-based perioperative anaphylaxis (POA) studies are limited to single center experiences. A recent report found that a serum acute tryptase (sAT) > 9.8 ng/mL or mast cell activation (MCA) can predict POA causal agent identification. Urinary mast cell mediator metabolites (uMC) have not been studied in POA.

OBJECTIVE: To analyze the epidemiologic data of POA, to determine if sAT or MCA can predict suspected causal agent identification, and to evaluate uMC utility in POA.

METHODS: Retrospective multicenter review of POA cases which were subcategorized by suspected causal agent identification status. sAT, MCA (defined as sAT >2+1.2 x serum baseline tryptase), and uMC (N-methylhistamine[NMH], 11β-prostaglandin-F2α [11β-PGF2α ], leukotriene E4 [LTE4 ]) were recorded.

RESULTS: Of 100 patients (mean age 52 [SD 17], 94% adult, 50% female, 90% White, 2% Hispanic) with POA, 73% had a sAT available, 41% had MCA, 16% had uMC available, and 50% had an identifiable suspected cause. POA cases with an identifiable suspected cause had a positive MCA status (100% vs 78%; p=.01) compared to POA with an unidentifiable cause. An elevated median sAT did not predict causal agent identification. Positive uMC were not associated with suspected causal agent identification during POA. Patients with positive uMC had a higher median sAT (30 vs 6.45 ng/mL; p=.001) and MCA status (96% vs 12%; p=.001) compared to negative uMC patients. Patients with POA had an elevated acute/baseline uMC ratios: 11β-PGF2α ratio > 1.6, N-MH ratio >1.7, and LTE4 ratio >1.8.

CONCLUSION: Presence of MCA in POA is associated with suspected causal agent identification. Positive uMC possibly correlate with a higher sAT level and MCA status but require further study. The authors suggest applying an acute/baseline uMC ratio (11β-PGF2α ratio > 1.6, N-MH ratio >1.7, and LTE4 ratio >1.87) in POA patients for MCA when a tryptase level is inconclusive during POA evaluations.